Objective: The purpose of this study was to investigate the effects of different durations of static progressive stretching (SPS) on posttraumatic knee contracture in rats, including range of motion (ROM), gait analysis, myofibroblast proliferation, and collagen regulation.
Methods: The posttraumatic knee contracture model was established, and male Wistar rats were randomly divided into the 20-minute SPS treatment, 30-minute SPS treatment (S30), 40-minute SPS treatment, untreated, immobilization, and control groups. At Week 1, 2, and 4 of treatment intervention, joint ROM and gait were measured and compared. Knee joint samples stained with hematoxylin and eosin and Masson trichrome were used to observe alterations in pathological structures. Collagen density and cell numbers in the posterior joint capsule were used to assess joint capsule fibrosis and inflammation. Immunohistochemistry was used to detect type I collagen and α-smooth muscle actin expression.
Results: The S30 group improved the most; ROM, stance, mean intensity, print area, and stride length were 115 (SD = 5) degrees, 0.423 (SD = 0.074) seconds, 156.020 (SD = 7.952), 2.116 (SD = 0.078) cm2, and 11.758 (SD = 0.548) cm, respectively. The numbers of myofibroblasts, fibroblasts, and inflammatory cells decreased, and collagen proliferation was significantly suppressed in the S30 group compared with the other groups.
Conclusion: S30 significantly improved posttraumatic knee contracture in rats, with reduced type I collagen and α-smooth muscle actin expression, decreased the numbers of myofibroblasts and inflammatory cells, suppressed fibrotic and inflammatory changes in the joint capsule, and increased joint mobility. This study provided basic evidence for an optimal standard-of-care treatment approach for posttraumatic knee joint contracture in rats, which may have significance for humans.
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http://dx.doi.org/10.1093/ptj/pzab300 | DOI Listing |
Am J Sports Med
January 2025
Department of Orthopaedics, Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island, USA.
Background: Meniscal injuries that fail to heal instigate catabolic changes in the knee's microenvironment, posing a high risk for developing posttraumatic osteoarthritis (PTOA). Previous research has suggested that human cartilage-derived progenitor cells (hCPCs) can stimulate meniscal repair in a manner that depends on stromal cell-derived factor 1 (SDF-1) pathway activity.
Hypothesis: Overexpressing the SDF-1 receptor CXCR4 in hCPCs will increase cell trafficking and further improve the repair efficacy of meniscal injuries.
PLoS One
January 2025
Lawrence Livermore National Laboratory, Physical and Life Science Directorate, Livermore, CA, United States of America.
Post-traumatic osteoarthritis (PTOA) is a painful joint disease characterized by the degradation of bone, cartilage, and other connective tissues in the joint. PTOA is initiated by trauma to joint-stabilizing tissues, such as the anterior cruciate ligament, medial meniscus, or by intra-articular fractures. In humans, ~50% of joint injuries progress to PTOA, while the rest spontaneously resolve.
View Article and Find Full Text PDFAm J Sports Med
January 2025
Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA.
Background: Anterior cruciate ligament (ACL) injury often leads to posttraumatic osteoarthritis (PTOA), despite ACL reconstruction (ACLR). Medial meniscal extrusion (MME) is implicated in PTOA progression but remains understudied after ACL injury and ACLR.
Hypothesis/purpose: It was hypothesized that MME would increase longitudinally after ACL injury and ACLR, with greater changes in the ipsilateral knee compared with the contralateral knee, leading to cartilage degeneration.
J Magn Reson Imaging
December 2024
Department of Radiology, Stanford University, Stanford, California, USA.
Background: Post-traumatic osteoarthritis (PTOA) often follows anterior cruciate ligament reconstruction (ACLR), leading to early cartilage degradation. Change in mean T fails to capture subject-specific spatial-temporal variations, highlighting the need for robust quantitative methods for early PTOA detection and monitoring.
Purpose/hypothesis: Develop and apply 3D T cluster analysis to ACLR and healthy knees over 2.
J Orthop Surg Res
December 2024
Department of Orthopaedic Trauma, Hebei Medical University Third Hospital, Ziqiang Road No.139, Shijiazhuang, Hebei Province, 050051, China.
Background: Posttraumatic osteoarthritis (PTOA) is directly associated with early acute articular cartilage injury. Inhibition of cartilage destruction immediately following joint damage can effectively slow or prevent PTOA progression. Therefore, we sought to determine intervention targets and therapeutic strategies in the acute stage of cartilage injury.
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